Differences in Influenza Seasonality by Latitude, Northern India - Volume 20, Number 10—October 2014 - Emerging Infectious Disease journal - CDC
Volume 20, Number 10—October 2014
Differences in Influenza Seasonality by Latitude, Northern India
Annual and pandemic influenza are sources of considerable illness and death worldwide (1). Human influenza infection rates peak during the winter months in temperate regions; however, the pattern of influenza is different in tropical and subtropical areas, with year-round circulation in some areas and biannual peaks in others (2–5). The complex seasonality of influenza in the tropics complicates appropriate vaccination recommendations, particularly the timing of vaccination campaigns in tropical regions (3,4).
India has discrete seasons that vary greatly from north to south. Jammu and Kashmir, the northernmost state of India, has severe winters from December to March, whereas Delhi, the capital region, has milder winters. Sentinel surveillance for influenza in India has shown distinct influenza peaks in India (6–8). We undertook influenza surveillance during 2011–2012 in 2 cities in northern India, Srinagar and New Delhi, which are ≈500 km apart, and found evidence for discrete seasonality related to the latitudes of these cities, a finding that has implications for influenza vaccination policy and timing.
Prof Koul heads the Internal and Pulmonary Medicine department in SheriKashmir Institute of Medical Sciences, Srinagar, India. His current research interests include pulmonary disease and respiratory infections, especially influenza and influenza vaccination.
We acknowledge the authors and originating and submitting laboratories of the sequences from the GISAID EpiFlu Database (http://www.gisaid.org) presented in the Technical Appendix.
This study was supported in part by cooperative agreement 5U51IP 000333 from the US Centers for Disease Control and Prevention (Atlanta, GA, USA).
- Simonsen L. The global impact of influenza on morbidity and mortality. Vaccine. 1999;17(Suppl 1):S3–10 .
- Tamerius JD, Shaman J, Alonso WJ, Bloom-Feshbach K, Uejio CK, Comrie A, Environmental predictors of seasonal influenza epidemics across temperate and tropical climates. PLoS Pathog. 2013;9:e1003194.
- Azziz Baumgartner E, Dao CN, Nasreen S, Bhuiyan MU, Mah EMS, Al Mamun A, Seasonality, timing, and climate drivers of influenza activity worldwide. J Infect Dis. 2012;206:838–46.
- Viboud C, Alonso WJ, Simonsen L. Influenza in tropical regions. PLoS Med. 2006;3:e89 .
- Park AW, Glass K. Dynamic patterns of avian and human influenza in east and southeast Asia. Lancet Infect Dis. 2007;7:543–8.
- Chadha MS, Broor S, Gunasekaran P, Potdar VA, Krishnan A, Chawla-Sarkar M, Multisite virological influenza surveillance in India: 2004–2008. Influenza Other Respir Viruses. 2012;6:196–203.
- Broor S, Krishnan A, Roy DS, Dhakad S, Kaushik S, Mir MA, Dynamic patterns of circulating seasonal and pandemic A(H1N1)pdm09 influenza viruses from 2007–2010 in and around Delhi, India. PLoS ONE. 2012;7:e29129.
- Koul PA, Mir MA, Bali NK, Chawla-Sarkar M, Sarkar M, Kaushik S, Pandemic and seasonal influenza viruses among patients with acute respiratory illness in Kashmir (India). Influenza Other Respir Viruses. 2011;5:e521.
- Centers for Disease Control and Prevention. CDC protocol of realtime RTPCR for swine influenza A(H1N1). 2009 Apr 28 [cited 2013 Jun 25].http://www.who.int/csr/resources/publications/swineflu/CDCrealtimeRTPCRprotocol_20090428.pdf
- Potdar VA, Chadha MS, Jadhav SM, Mullick J, Cherian SS, Mishra AC. Genetic characterization of the influenza A pandemic (H1N1) 2009 virus isolates from India. PLoS ONE. 2010;5:e9693.
- Saha S, Chadha M, Mamun AA, Rahman M, Sturm-Ramirez K, Chittaganpitch M, Influenza seasonality and vaccination timing in tropics and subtropics of south and south-east Asia. Bull World Health Organ. 2014;92:318–30.
- Western Pacific Region Global Influenza Surveillance and Response System. Epidemiological and virological characteristics of influenza in the Western Pacific Region of the World Health Organization, 2006–2010. PLoS ONE. 2012;7:e37568.
- Moura FE, Perdigao AC, Siqueira MM. Seasonality of influenza in the tropics: a distinct pattern in northeastern Brazil. Am J Trop Med Hyg.2009;81:180–3.
- Yu H, Alonso WJ, Feng L, Tan Y, Shu Y, Yang W, Characterization of regional influenza seasonality patterns in china and implications for vaccination strategies: spatio-temporal modeling of surveillance data. PLoS Med. 2013;10:e1001552.
- Cox N. Influenza seasonality: timing and formulation of vaccines. Bull World Health Organ. 2014;92:311.
Suggested citation for this article: Koul PA, Broor S, Saha S, Barnes J, Smith C, Shaw M, et al. Differences in influenza seasonality by latitude, northern India. Emerg Infect Dis [Internet]. 2014 Oct [date cited]. http://dx.doi.org/10.3201/eid2010.140431
1These authors contributed equally to this article.
2Current affiliation: INCLEN Foundation, New Delhi, India.
Figure 2. Comparison of latitudes of Srinagar and New Delhi, India, and distribution of influenza virus infections, 2011–2012. A) Locations of Srinagar and New Delhi (black triangles), with vertical lines indicating 30°N latitude...